I had this item (Stone of Light) drop for me in Yxtta today, off "an unmasked changeling". I was fighting "a ra`tuk destroyer" in the temple east of Jerimo Jiao, when it turned into "an unmasked changeling" (like those which randomly spawn in Infected Paw, added when Infected Paw was a hotzone) with the same graphic as my character.

Note that the mob cast the spell "Phantasmal Shift" just before it turned into the "an unmasked changeling".